Cellulosic textiles, prior to dyeing or printing in commercial operations, usually undergo treatment with caustic to remove fats, oils or other materials. The process is called "scouring" and is generally performed with a solution of caustic soda at elevated temperatures. Following the scouring process, the fabric is subjected to steaming.
To improve the whiteness of the fabrics, the fabrics are usually subjected to a bleaching step with a peroxide solution. Following bleaching, the fabrics are also subjected to steaming, washing and drying.
However, there are fabric treating operations which do not employ caustic scouring baths. In place of scouring a two step bleaching operation is commonly utilized.
It is known to treat cotton with quaternary salts to improve its dyeability. Choline chloride has been utilized but it has the drawback of being sensitive to changes in curing temperature.
The presence of the quaternary compound in the bleach bath results in a greater uptake of any anionic fabric brightener.
U.S. Pat. No. 3,685,953 to Cavelier et al, which is herein incorporated by reference, discloses the utilization of an epoxypropyl ammonium salt with a strong mineral base as a fixation catalyst during scouring in order to improve the dyeability of cellulosic fibers. The epoxypropyl ammonium salt is used with at least 0.5% of the base as a catalyst to cause fixation of the epoxypropyl ammonium salt.
The measurement of colors in the present application is pursuant to the Adams-Nickerson or AN/AB space known as CIELAB. In this color space, "a" represents red/green, "+a" being red, "-a" being green, "b" represents yellow/blue, "+b" being yellow, "-b" being blue.
The term "fabric" as used herein is intended to include textile materials such as filaments, yarns, tows, battings, woven and non-woven cloth, knitted fabric and the like.